Objective To study the homology characteristics of clinicaly isolated and colonized linezolid(LZD)-resistant Enterococcus faecalis (E.faecalis) strains from a patient.Methods Ten E.faecalis strains (2 were isolated from urine specimens and 8 were from stool specimens) isolated from a patient with pulmonary infection were performed antimicrobial susceptibility testing, homology of E.faecalis was determined by pulsed-field gel electrophoresis (PFGE).Results Before and after patients received LZD therapy, 2 E.faecalis strains isolated form urine specimens were both resistant to LZD (MICs: 8 mg/mL, 16 mg/mL, respectively), among 8 strains from stool specimens (6 were isolated before therapy, and 2 were isolated after therapy), LZD susceptible, intermediate, and resistant strains were 4, 2, and 2 respectively(MICs: 0.25-12 mg/mL).10 strains of E.faecalis were homologous by PFGE typing.Conclusion In this case, the detection of E.faecalis from urinary tract and intestinal tract is homologous, which suggested that LZD-resistant Enterococcus may be colonized in vivo for a long time, and may be shift to cause bacterial infection.

Objective To understand genetic mutation sites in linezolid (LZD)-sensitive and inducible resistant strains of methicillin-resistant Staphylococcus aureus (MRSA) using whole-genome sequencing,and realize mutation sites of LZD-resistant gene.Methods MRSA-MS4 with explicit genotype and whole-genome sequences was induced by LZD of different concentration gradients,LZD-resistant strain MRSA-MS4-LZD100 was obtained,minimum inhibitory concentration(MIC) was detected,domain V of 23S rRNA and ribosomal proteins L3/L4 gene in MRSAMS4-LZD100 were amplified by polymerase chain reaction (PCR),the sequenced products obtained the corresponding mutation site in contrast with the wild-type strain;Illumina PE library was constructed through paired-end sequencing by Illumina HiSeq 2000 technique,and whole genome sequencing was completed based on bioinformatics.Results MRAS-MS4-LZD100 strain was induced after 32 passages,MIC of LZD was 96 μg/mL.Sequencing of PCR products indicated the genetic variations were G2447T mutation in multiple copies of domain V of 23S rRNA gene,and Gly113Val mutation in L3 protein respectively;the whole genome of MRSA-MS4-LZD100 contained 2 744 315 bp,annotation of the whole genome found a total of 2 509 genes,11 tRNA-encoding genes and 2 entire rRNA-encoding operons.The data were submitted to the PubMed,and the GeneBank accession number JXMJ00000000 was assigned;a total of 101 SNPs and 6 Small indels were found,16 of 101SNP mutations occurred in exon,of which the variant proteins with anmino acid sequence alterations included IstB ATP binding domain-containing protein,clumping factor A,IS1272 transposase and so on;3 of 6 Small indel mutations occurred in exon,of which the variant proteins with anmino acid sequence alterations included hypothetical protein,30S ribosomal protein S1,and clumping factor A.Conclusion LZD-resistant strain MRSA-MS4-LZD100 was successfully induced by LZD;beside 23S rRNA V domain and ribosomal L3 protein,the other mutant site exist in this resistant strain,which provide some direction for subsequent study of recessive LZD resistance mechanism.

Major challenges for cancer treatment are how to effectively eliminate primary tumor and sufficiently induce immunogenic cell death (ICD) to provoke a robust immune response for metastasis control. Here, a self-assembled cascade bioreactor was developed to improve cancer treatment with enhanced tumor penetration and synergistic therapy of starvation, chemodynamic (CDT) and photothermal therapy. Ultrasmall FeS-GOx nanodots were synthesized with glucose oxidase (GOx) as template and induced by paclitaxel (PTX) to form self-assembling FeS-GOx@PTX (FGP)